Free CSS Unit Converter — px to rem, em, vw, vh, % and More
Convert CSS pixel values to rem, em, %, vw, vh, pt, cm, and mm instantly. Set your root font size and viewport dimensions for accurate context-aware conversions.
Key Features
- Convert px to rem, em, %, vw, vh, pt, cm, mm
- Set root font size, parent font size, and viewport dimensions
- Quick-click reference for common sizes (4px to 96px)
- One-click copy for any converted value
SimplyUtils vs Competitors
| Feature | SimplyUtils | Nekocalc | Codebeautify | CSS Values |
|---|
| Multiple output units | ✓ | ✓ | Partial | ✓ |
| Context settings | ✓ | ✓ | ✗ | ✗ |
| Quick reference panel | ✓ | ✗ | ✗ | ✗ |
| Free to use | ✓ | ✓ | ✓ | ✓ |
Frequently Asked Questions
What is rem and why should I use it?
rem (root em) is relative to the root element's font size (usually 16px). Using rem for font sizes and spacing makes your design scale consistently when users change browser text size, improving accessibility.
When should I use vw/vh?
vw (viewport width) and vh (viewport height) are useful for full-screen layouts, responsive typography, and elements that should scale with the browser window size.